N petre



April 20, 1954 N P TR 2,675,742

METHOD FOR FORMING FLUTED BITS UPON AN END OF A SHANK OR A SCREW DRIVEROriginal Filed Feb. 1, 1951 8 Sheets-Sheet l o '2 o m 5.3 N m N M i a asEv" 5 j "--*:&-aa O Q LO Q a a w R & o &

I o l Q fl 00 s Q 0 V) 8a o O I i O Q: i b w l 1.

. a I ii I i h i or Fig). 20.

Jnventor (lttomeg.

PETRE April 20, 1954 J. N. METHOD FOR FORMING FLUTED BITS UPON AN END OFA SHANK OF A SCREW DRIVER Original Filed Feb. 1 1951 8 Sheets-Sheet 2.D. 5 g $5 Qa L, L

Bummer wwwwm wwa Na Tmm mt 3 EM 33 Q TiwL m vikliuw rlitx w 5 4 ax JohnN. Patna, QDQJJQW (Iitornag J. N. PETRE METHOD FOR FORMING FLUTED BITSUPON AN END OF A SHANK OF A SCREW DRIVER Original Filed Feb. 1, 1951 8Sheets-Sheet 3 CC\ m; c i @EQRQQG MQNQQN RQQNQQQ aw 2M2 m a v Um U i J NQ Q a ga w 0 m9 8 INN, mm w w l 11111 1 I w w m w uh"HHHmHHHHHHSHH mm JQM o WM. 3 i M 8m QQE m o) n) Q. wk 8N 3m ma am mow Q Q m mfi 4T- Q 3T93 0 N8 O a, 3 Q E 251 $8 g k wg fi gig swmw Aprll 20, 1954 N. PETR2,675,742

METHOD FOR FOR LUTED S UPON AN END OF A SHANK A SCREW DRIVER OriginalFiled Feb. 1, 1951 8 Sheets-Sheet 4 1-! l a-aw M Qttorneg April 20, 1954PETRE 2,675,742

METHOD FOR FORMING FLUTED BITS UPON AN END SHANK OF A SCR EW DRIVER 8Sheets-Sheet 5 OF A Original Filed Feb. 1, 1951 Qm\ \m m\ m H [\Q Ziii:@m g v A: N W n W G: f g a w; J m Q a Q .Q x {II w 4% ww-a 5 w a .J 6% am E M r 2.69 Q33 \g N @Rwg l E WF w: 2 a E m PETRE LU April 20, 1954 J.N. RMING F A SHANK OF A EW DRIVER METHOD FOR F0 OF Original Filed Feb.1, 1951 T a Q 3% NE 3% 3 E m 7 h 4 MLIM- N m 57/ Iilfi- F J M W \M a? Q1 \Q L m vy v Kw? my 1 i r NW Ma Q U a Q \E Q & MN mm 5 Q N mm mm 3 N 3g Q g U Q gagaia N? b 65/ \L 7 1 @T a n pm 9% MM g x w m 8 9E S a m ow hon w 2 Clttorncg Jnvzutor John Pefre,

6 C(tiomag 8 Sheets-Sheet 7 TED BITS UPON AN END SCREW DRIVER E A m m EH& nmm

a n W :a w 1, JHKAQ I H mm 4M w M i .Q 5 1. m a w. M 6 m m .1 w N A m 3g aw maxim Q 3 2,675,742 BITS UPON AN END EW DRIVER April 20, 1954 ET EMETHOD FOR FORMI FLUTED A SHANK OF A SCR 8 Sheets-Sheet 8 Original FiledFeb. 1,

Inventor John N. PQJTQ,

attorney Patented Apr. 20, 1954 METHOD FOR FORMING FLUTED BITS UPON ANEND OF A SHAN K OF A SCREW DRIVER John N. Petre, Orchard Park, N. Y.,assignor to XceLite, Incorporated, a corporation of New York Originalapplication February 1, 1951, Serial No.

Divided and this application March 8, 1952, Serial No. 275,620

3 Claims. 1

This invention relates to a method for. forming fluted bits upon an endof the shank of a screw driver. The subject matter herein. claimed isdisclosed in. an application filed by me for a machine for forming screwdriver bits of the fluted type, said application being Serial No.

208,877 and having been filed February 1, 1951,

and the present application being a division thereof.

Screw drivers of the fluted bit type are. known in the trade as Phillipsscrew drivers and are of the substantial construction shown anddescribed in the Phillips patent, No. 2,046,837, and the Phillips andFitzpatrick patent, No. 2,046,840, both of which were issued on July 7,1936. Such screw drivers are cooperative with screws of the particulartype which are known in the trade as Phillips screws. These screws areof the substantial construction shown. and described in the PhillipsPatent N 02,046,837 and the Phillips and Fitzpatrick patent, No.2,046,839, also issued on July 7, 1936, and are characterized by socketsof special form in their heads. These sockets provide webs which, inrelation to the vertical or longitudinal axes of the sockets, are ofre-entrant angular contour and have rather sharp apices which extenddownward from the upper face of the screw head. The webs are separatedand delimited by recesses which extend radially in relation to thevertical or longitudinal axes of the socket.

The fluted bits are generally polygonal in cross section and conformgenerally in crossv sectional contour to the cross sectional contour ofthe sockets in the heads of the Phillips screws. The conforming crosssectional contours of the bits and the sockets in the screw heads may bevaried as shown, for example, on Sheet 2 of the drawings of the PhillipsPatent No. 2,046,837. In practice, however, the bits and cooperatingscrew head recesses have been made of general cruciform outline.

The method of the invention is available for the production of flutedbits of various cross sectional contours. For a clear understanding ofthe method it is deemed advisable to show and describe in thisapplication a machine by which the method is practiced. As hereindisclosed the machine is designed for the production of fluted bits ofthe general cruciform outline which accords with standard usage.

In the construction which has become standard the flutes of the bits areseparated by equidistantly spaced vanes which provide the flute sidewalls and the side walls of each flute extend inward in convergingrelation and meet along a line located in a central. longitudinal planeof the shank. This line may be said to be the base, of the flute andextends upward and Outward from the terminal of the bit. Thus the flutebases have an upwardly diverging mutual relation. When the bit is fittedin the socket of the screw head the bases of the flutes engage the upperends, of the apices of the re-entrant screw head webs with wedgingeiiect, the vanes conformably fit within the recesses of the socket withkeying eflect (that is to say for the purpose of rotation theypositively couple the bit as wedged in the socket to the screw head) andthe core of the bit is located within the central portion of the socket,i. e., the. portion of the socket bounded by the apices of the webs. Theflutes are formed by rotary cutters and their bases have an incidentalconcave. curvature. in lineal outline, this curvature being so gentleor, more exactly, about such a long radius, that it does not interferewith the proper, i. e. functioning, angularity of the base of the flute.The angularity of the bases of the flutes with reference to thelongitudinal axis of the bit is of quite small degree and in practice,according to circumstances, may be varied within narrow limits.Generally speaking the angularity of the bases of the flutes is of the.order of from five to ten degrees. It will, of course, be understoodthat such angularity and the longitudinal and. transverse dimensions ofthe bits will be varied in accordance, with the varying dimensions ofthe screw heads and their sockets. within the range of manufacturingsizes. In other words each bit is especially designed for coordinationin use with a screw head socket of some particular longitudinal andtransverse dimension.

In the machine heretofore used for the formation of the fluted bit of aPhillips screw driver the flutes are out, one at a time, in successiveoperations. For this purpose a single rotary milling cutter is providedand the shank, suitably mounted to secure the requisite angularity ofthe longitudinal out which provides the flute, is fitted in a rotatableindex feature. Four separate and successive cutting operations arerequired. Thus the shank is advanced toward the cutter for the first cutand is then withdrawn; utilizing the index feature it is then turnedabout its axis to the appropriate number of degrees, i. e., ninetydegrees for a bit of cruciform cross section, and is again advancedtoward the cutter for the second out and, again withdrawn. Theseoperations are continued until four cuts: have been made. In connectionwith the repetition of these operations the angularity of the shank mustbe appropriately changed for each successive cut in order to insure theappropriate angularity of the base of the flute. The cutter exerciseslateral pressure upon the terminal portion of the shank. In somemachines special provision is made for opposing such lateral pressure.In many machines the lateral pressure is unopposed. Unopposed lateralpressure, particularly where the shanks are relatively thin, frequentlyresults in the distortion of the terminal portion of the shank duringthe cutting operation as a consequence of which the flutes will be ofimproper formation, or relation. When this happens the shank must bediscarded.

The prior machines, because they can out only one flute at a time,impose the necessity of separate and successive cutting operations, theintermediate operations of the index feature, and the intermediatechanges in the position of the shank in order to insure the properangularity of the base of the flute. It follows that the formation ofthe flute bit requires an extravagant period of time and the productioncapacity of the machine is relatively low. In prior machines where thecutter exercises unopposed lateral pressure upon the shank an additionalfactor which lowers the production capacity is thereby introduced, notto mention the waste represented by shanks that are necessarilydiscarded.

The invention accomplishes the following broadly stated objects, viz.: aseries of simultaneously produced preliminary cuts, one for each flute,followed by the cutting of all of the flutes simultaneously; theneutralization of lateral pressures exercised upon the shanks during thecutting operations; the planishing of the flutes upon the completion ofthe cuts; and pro vision for predeterminately varying the angularity ofthe flute bases and the lineal and cross sectional dimensions of theflutes as circumstances may require. By virtue of these objects, thefollowing substantial advantages are achieved, via: without increase oflabor the production capacity of the machine is several times greaterthan the production capacity of the prior machines, i. e., between threeand four times greater; thus whereas the prior machines have an averageproduction capacity of six hundred fluted bits per day, the inventionenables the production of twenty-two hundred fluted bits per day; theflutes are out with the greatest possible speed; all liability ofdistortion of the shanks during the flute cutting operation is avoidedand uniform and perfectly formed flutes are always produced; expensiveWaste, represented by malformed flutes and discarded shanks, iseliminated; without any separate operations or separate operatingfeatures the flutes are effectively planished and freed from all burrsor surface irregularities; and bits may be produced to conform toPhillips screws as varied throughout the manufacturing range.

The invention consists in the novel steps and conditions of the method.

In the accompanying drawings:

Figure 1 is a front elevation of a machine for carrying out the methodof the invention and which is constructed to form fluted bits forgeneral cruciform outline, the machine being of the construction whichforms the subject of my copending parent application, Serial No.208,877.

Figure 2 is a bottom plan view of the machine.

Figure 3 is a horizontal sectional view on the line 3-3 of Figure 1,looking in the direction of the arrows, various openings in the tablefor cooperation with sundry attachment belts or screws being omitted.

Figure 4 is a perspective view of a portion of a cam ring with anattached cam, this being one of a series of similar cams mounted on thering and used for raising and lowering the several cutters.

Figure 5 is a top plan view wherein the table of the machine is partlybroken away, this view being limited to the showing of sundry featuresof a pneumatic system for controlling the operation of various parts ofthe machine.

Figure 6 is a cross section on the line 6--t of Figure 3 showing a gagefor insuring the proper initial location of the shank relatively to thecutters which form the flutes and also showing a collet which is fittedupon the shank and by means of which the shank is properly positioned inthe machine, this collet, as a matter of convenience, being referred toas a locational collet.

Figure '7 is a side elevation of the shank and the locational colletapplied thereto, this figure assuming the previous use of the gage shownin Figure 6.

Figure 8 is a view partly in longitudinal section and partly in sideelevation of one of two similar automatically operative pneumatic valvesof the four-way type for the operation and control of certain mechanismsincorporated in the machine.

Figure 8a is a plan View of the base plate of the automatic valve shownin Figure 8, a plate valve which forms a part of the automatic valvebeing shown in horizontal section.

Figure 8b is a central longitudinal section of a bleeder valve, severalof which of similar construction are incorporated in the pneumaticoperating and controlling system which includes the two four-way valvesof the construction shown in Figure 8.

Figure 9 is an enlarged partial top plan view of the machine showing thecarriage for the shank and sundry mechanical features associ ated withthe carriage together with parts of the cams shown in Figure 4 and thering upon which the cams are mounted, the cutter unitsbeing omitted fromthis figure in order to promote clarity of illustration.

Figure 10 is an enlarged partial top plan view of the machine showingthe arrangement of the cutter units and the gearing for the operation ofthe cutters, the carriage for the shank being partly broken away inorder to promote clarity of the illustration.

Figure 11 is a vertical sectional view on the line H-H of Figure '10,looking in the direction of the arrows.

Figure 11a is a fragmentary sectional View in the same plane as Figure11 and showing on a larger scale certain details of a guide bar and itsmounting.

Figure 12 is a vertical sectional view on the line l2--I2 of Figure 9,looking in the direction of the arrows.

Figure 13 is a vertical sectional view on the line l3l3 of Figure 9,looking in the direction of the arrows.

Figure 14 is a vertical sectional view on the line |4M of Figure 9,looking in the direction of the arrows.

Figure 14a is a perspective view of a block which carries an operatingarm for a bleeder valve.

Figure 15 is a detail vertical sectional view on the line l5-l5 ofFigure 14, looking in the direction of the arrows.

Figure 16 is a perspective view of the cam mechanism for effecting andcontrolling the movements of the carriage for the shank.

Figures 17 to 20 illustrate the method.

Figure 1'7 is a diagrammatic view showing the shank in the course of itsdownward movement relatively to the cutters as having reached theposition. wherein the preliminary cutting action is initiated.

Figure: 18 is a diagrammatic view showing the relation of the shank andthe cutters at the beginning of the flute cutting operation.

Figures 19 to 22 appear on. Sheet 1.

Figure 19 is a diagrammatic view, corresponding to the diagram of Figure18, showing the shank as completely-moved into operative relation to thecutters and in a relative position wherein the preliminary cuts havebeen completed and the cutting of the flutes is initiated, the axes ofthe cutters at such time being in their normal or lower commonhorizontal plane,

Figure 20 is a similar diagrammatic view showing the relation betweenthe cutters and the shank at the completion of the formation of the bit,the cutters having been moved to a position wherein their axes are in acommon horizontal plane above their normal horizontal plane.

Figure 21 is a side elevation of a terminal portion of the shank uponwhich the fluted bit has been formed.

Figure 22 is an end elevation of the bit shown in Figure 21.

The various parts of the machine are supported by a horizontal table Imounted upon legs 2- which are, preferably of channel cross section andare provided at their upper ends with horizontal flanges 3. andat theirlower ends with horizontal plates 4 (Figures 1, 2 and 11). The legs 2are arranged adjacent the ends of the table I. The flanges 3 providedirect support for the table and are secured to the table in anysuitable manner, e. g. as by screws 5. The plates 4 rest upon the floorand provide, floor engaging surfaces of suitable extent to insure thestability of the machine.

The principal elements of the machine are a carriage designatedgenerally as s for holding the screw driver shank S (Figures 1-1 and12), a series of milling cutter units designated generally as 5 (Figuresand 11):, and a mechanism designated generally as 8 (Figures 2, 4,. 9and 11) for effect ing the upward and downward. movements of the millingcutters.

The shank holding carriage The shank holding carriage 6 includes ahorizontal bar 9 supported for positively guided rectilinear movementabove the milling cutter units and having two positions, viz., a normalupper or distant position and an operative lower or near position.Adjacent one end (its left end, Figures 1, 11 and 12 being considered)the bar 9 is mounted for vertical sliding movement upon a vertical postIn. On. its lower face the bar 9 carries a collar H slidablysurroundingv the post I!) and providing a shoulder 12. The post It iscarried by and extends upright from a suitably formed bracket 13attached to the table I and providing an annular shoulder 14. Anexpansive helical spring 15 surrounds the post It and is located betweenand reacts against the shoulders 12 and I4. Adjacent its opposite. end(its right end, Figures 1, 13, 1 1 and 15 being considered) the bar 9rests upon a spring supported horizontal plate 16 suitably mounted forvertical movement and positively guided in its movements. As shown, theplate It is connected to the upper ends of a pair of vertical posts I!which fit slidably in sockets I8 in a fixed block 19 (convenientlyattached to the standard 23 to be later described). An expansive helicalspring 2! surrounds each post I1 and is located between and reactsagainst the base of the socket I8 and the under face of the plate I6.The upper face of the plate It has a terminal bevel formation 2|adjacent an edge face (Figures 13 and 15) which is utilized when the bar9 is swung about the post It as a pivot from an inoperative position(dot and dash lines in Figure 9) to its normal position in the upperplane (Figures 13 and 14 and, broken lines, Figure 19).

The table I carries a pair of upright standards 22 and 23 (Figures 1, 9and 10) secured by bolt fastenings 24. The standard 22 is formed with arecess 25 open to a vertical face. Thestandard 23 is formed with asimilar recess 26. The recesses 25 and 26 are presented inopposite-directions, i. e., the standard 22 at the left end of themachine (Figure 1) has its recess 25 open to its rear face and thestandard 23 at the right end of the machine has its recess 26 open toits front face. Each of the recesses 25 and 26 (Figures 14 and 15)provides outer and inner shoulders. Corresponding shoulders are atcorresponding locations on the standards and their planes are thereforeparallel. As herein disclosed the shoulders are in upper and lowerrelation. The outer shoulder is preferably in the form of a horizontalanti-friction roller 21 having trunnions moutned in opposed verticalwalls of the recess. The roller 21, with its lower side exposed in therecess, overhangs the flat horizontal inner shoulder 28 which ispreferably coextensive with the width of the bar ii. The rollers 21'limit the upward movement of the bar 9 as effected by the springs l5 and20 and. the shoulders 28 limit the downward movement of the bar 8 andprovide stable rests for the bar 9 in its lower position.

The mechanism for operating the shank holding carriage The rollers 2'!also cooperate with the mechanism, indicated generally at 22 (Figures 1,9 and 16), for effecting the movement of the bar 9 from its. upperposition to its lower position. This mechanism includes a straighthorizontal operating lever 39 having two alining arms 3| and 32 whichmay be said to be delimited by a pivotal connection 33. between thelever 30 and the bar 9. The pivot 33 extends through a suitably locatedopening 34 in the lever 39 and is fitted in or to the bar 9 and also ina bracket 35 (Figures 9 and 4:) secured to the bar 9 and overhanging thelever 30. The arm 3| projects in a rearward direction beyond the pivot3'3 and the arm 32 projects in a forward direction. The arm 31 ispivotally connected near its outer end to a horizontal link 36 and thearm 32 is similarly pivotally connected to a horizontal link 31. Thelinks 35 and 3'! extend in opposite directions from the lever 38, thelink 36. extending to the right (Figures 9 and 16' of the drawing beingconsidered) and the link 31 extending to the left. The link it ispivotally connected at its outer end to. a horizontally extending cammember 38 of the slidable wedge type and the link 3? is pivotallyconnected at its outer end to a horizontally extending cam member 39similar in all respects to the member 33. The members 38 and 39 haveflat bottom faces and rest directly upon the bar 9. Their movements ineither direction, as directly effected by the links to which they areconnected, are longitudinally of the bar 9' and they are positivelyguided in such movements. For this purpose the members 38 and 32 areformed adjacent their bottom. faces and at each side with laterallyprojecting straight longitudinal flanges All and are slidable in waysprovided by guides 4| and 42, the guide 41 being attached to the frontface of 7 the bar 9 and the guide 42 being attached to its upper face.The guides 4| and 42, as shown in Figure 13, are formed for overhangingengagement with the flanges 40 and thereby confin the cam members in theguide ways. The upper faces of the members 38 and 39 are fashioned toprovide the cam action and, for a purpose to be later described, have atwo-stage inclination. The first stage is provided by an inclined face43 and the second stage is provided by an inclined face 44. The inclinedface 43, which may be called the outer cam face, terminates at the outerend of the cam member and the inclined face 44, which may be called theinner cam face, extends between the face 43 and the upper face of thecam member. The face 43 has a greater degree of inclination than theface 44. Thereby the face 43 effects a relatively quick action and theface 44 effects a suitably slower action. In the operation of themechanism power is applied to the arm 32, the length of which is suchthat if casion should require it may be used as a handle for the manualoperation of the mechanism. In the normal relation of the parts as shownin Figures l and 11 the bar 9 is in its upper position (whichcorresponds to the position shown in broken lines in Figure 19) and thewedge members are interposed to some extent between the rollers 21 andthe upper face of the bar 9, the rollers 21 at such time resting uponthe outer cam faces 43. With the parts in this relation the lever 39, bythe application of power to its arm 32, is moved about the pivot 33 inorder to effect outward movements of the links 36 and 31 and of the cammembers 38 and 39. Figure 9 of the drawing being considered, thismovement of the arm 32 is to the left and is continued until the leverreaches the position shown in broken lines. This movement of the lever30 causes the cam faces 43 and 44 to react successively against therollers 2'! with the result that the bar 9 is given rectilinear downwardmovement in opposition to the pressure of the springs I and 20. At thecompletion of the outward movements of the cam members 38 and 39 therollers 21 engage their upper flat faces and thereby positively hold thebar 9 in its lower position as shown in full lines in Figure 19. Thedownward movement of the bar 9 caused by the reaction of the outer camfaces 43 against the rollers 21 is at a more rapid rate than thecontinued downward movement of the bar 9 caused by the reaction of theinner cam faces 44 against the rollers 21. The transverse lines 45 atwhich the cam faces 43 and 44 adjoin substantially correspond inlocation to the horizontal plane P (Figure 17) in which the shankinitially engages the teeth of the cutters, this being the plane inwhich the later described preliminary cutting action is initiated. Inaid of speed of operation it is desirable that the initial downwardmovement of the shank, i. e., its movement prior to its engagement withthe cutters, be quite rapid and the inclination of the outer cam faces53 is determined with thi consideration in mind. In order to preventinjury to the shank or the cutters it is desirable that the downwardmovement of the shank immediately following its engagement with thecutters be not too rapid. It is for this reason that the inner cam faces44 have less inclination than the outer cam faces 43. The abovedescribed movement of the lever 30 which results in the downwardmovement of the bar 9 is positively limited. This is accomplished by abumper arm 45 located below the link 3! and secured by fastenings 46a tothe bar 9, the arm 46 projecting forwardly and inwardly from the bar. Asan additional factor in the prevention of injury to the cutters or tothe shank the arm 46 carries at its outer end a slidably mounted springbiased projecting bumper head 47 which is engaged by the arm 32 at asuitable point in its movement, i. e. a point substantiallycorresponding to the initial points of engagement of the inner camsurfaces 44 with the rollers 27, to cause the lowering of the bar 9 at aslower rate, and which retards and progressively cushions the continuedoperative movement of this arm.

The method The milling cutters 48 are of the same diameter and arearranged in angular and equally spaced relation with their axes ofrotation in a common plane H (Figure 18) which is horizontal in theembodiment disclosed. In this plane the peripheries of the cutters arespaced to delimit a passage 49 of symmetrical contour (Figures 10, 19and 20) Figure 18 shows a shank S properly positioned for the cutting ofthe flutes. In the practice of the method the shank S, which has adiameter suitably greater than the minimum sectional dimension of thepassage 49, is moved in the direction of its vertical axis A and in adirection normal to the plane H into the passage, the axis A being inalinement with the axial center of the passage 49. The movement of theshank is continued to a point at which the lower ends of the bases ofthe fiutes at the initiation of the cutting of the flutes will liewithin a horizontal plane P. This plane is located below the plane P andmay be in substantial coincidence with the plane H or it may, as hereinshown, be slightly above it. The plane P prescribes the points E atwhich the succeeding step, namely the cutting of the flutes, commences,these points coinciding with the lower ends of the bases of the flutes.The angle of the bases of the flutes to the axis A of the shank is inany case less than the angle of the bases of the preliminary cuts C(Figure 18) to the axis A. The location of the plane P is such that thepoints E; will lie with'm upwardly diverging lines T-tangential to thecut ters and at an angle to the axis A which substantially correspondsto the general angle of the bases of the flutes to the axis A. In Figure18 it may be assumed that the bases of the flutes are to extend at anangle of the order of seven degrees to the perpendicular, i. e., theaxis A, in which case the tangent lines T will extend at an angle ofseven degrees to the axis A. The tangent lines T extend at right anglesto lines R which extend to the points E and are radii of the cutters.The angle of the lines It to the plane H is the same as the angle of thelines T to the axis A. For example if the angle of the lines T to theaxis A be assumed as seven degrees the angle of the lines R to the planeI-I will be seven degrees.

When the shank S is moved into the passage 49 to the position determinedby the plane P (as shown in Figure 1'?) the cutters 48, during the finalstage of the downward movement of the shank, will make preliminary cutsin the end of the shank, these conforming in basal lineal outline to thecurvature of the cutters and facilitating the cutting of the flutes. Theterminal portion of the shank (upon which the bit is to be formed) is ofan outline which tapers to a point as shown at Y in Figure 17 from anannular line X at the cylindrical surface of the shank, a standardpointing machine being used for this purpose. The taper Y provides thesocket engaging terminal portion Z of the bit (Figure 21), the taper ofwhich conforms to the taper of the socket in the screw head. Thepreliminary cutting commences during the downward movement of the shankwhen the line X of the shank substantially coincides with the plane P.This relation is shown in Figure 17. The preliminary cuts are completedwhen their lower ends coincide with the points E in the plane P. Figure18 shows the preliminary cuts as completed, their outline and extent,both above and below the line X of the shank, being indicated by brokenlines C. The flutes are cut from points quite near the lower end of theshank to points on its cylindrical surface, these latter points beingthe upper ends of the bases of the flutes. The cutting of the flutes isaccomplished by holding the shank stationary and at the same timeeffecting simultaneous coextensive movements of the cutters in angulardirections having components opposite to the direction of movement ofthe shank and outward components of the same degree of angularity. Inthe embodiment disclosed these movements are upward and outward. Figure20 assumes the complete cutting of the flutes. The tangent lines Tconform in angularity to the movements or" the cutters. Thus for thestep of cutting the flutes the cutters are moved angularly upward fromtheir normal positions N (broken lines) to or through raised positions(full lines) wherein their horizontal axes are in a common plane Hparallel to the plane H and coincident with the upper ends of the basesof the flutes. Hence, the elevation of the-plane H, indicatedarbitrarily in Figure 18, will accord with the prede with the upper endsof the bases of the flutes. When the axes of the cutters reach the planeH the cutting of the flutes is completed and thereupon, the shank beingheld stationary the while, the cutters are returned to their normalposition, represented by the plane H, by an inward and downward movementalong the same paths as their upward movement during which the cuttersact with planishing effect upon the flutes. After the cutters 48 havebeen returned to their normal lower positions the bar 9 is returned toits normal upper position. This is accomplished by the application ofpower'to the arm 32 whereby to move it back into its normal positionshown in full lines in Figure 9. At such time the cam members 33 and 39are withdrawn and the springs iii and 2t raise the bar 9 until itsmovement is arrested by the rollers 27.

The gage for determining the position of the locational collet For thesatisfactory use of the screw drivers accuracy, approaching precision,is required in the formation of the bits. For this purpose the bit mustbe accurately located in the machine. This is accomplished by alocational collet 5d (Figures 6 and '7) which is preierably'in the formof an open ended sleeve split from one end to a point suitablyintermediate its length, thereby to provide a pair of opposed resilientclamping jaws 51 of semi-circular cross section and which tend to springinward. The collet is engaged with the upper portion of the shank S andthe distance D to which the shank projects beyond the collet is requiredto be exactly of a predetermined extent. This extent will be the samefor screw drivers which requireexactly similar bits. However, since therange of manufacture will require bits of various dimensions extent intothe casing 53.

the extent D to which the-shank S projects beyond the collet must beselected to accord with the particular bit which is to be formed andhence will be varied accordingly as the bit may conform to one oranother set of dimensions. The selection of the extent D is effected bya suitable gage designated generally as 52 and which includes a verticaltubular cas ng 53, open at its upper end and formed with internalthreads 54 extending for a suitable distance from its lower end. Thelower end of the casing '53 is closed by a screw stem 55 which projectsinto the casing and engages the threads '54. The stem 55 is held in anyposition to which it may be adjusted by a lock nut 56 which bearsagainst the lower end of the casing "53 and is provided at its lower endwith a head '51 by means of which it may be positionably adjusted, thatis to say, adjusted to project to a greater or "less The stem 55 and thecasing 53 delimit a vertical well 58, the extent of which determines thedistance D and the internal diameter of which slightly exceeds themaximum shank diameter within the manufacturing range. For a bit of someparticular set of dimensions the required depth of the well 58 isdetermined by any appropriate shop measuring tool, the position of thestem 55 being adjusted to conform to and prescribe this depth. Thedistance D is the same for all bits which conform to a particular set ofdimensions. 'When bits of another set of dimensions are to be made acorresponding change in the depth of the well 58 is required and thestem55 is adjusted to effect this change, the extent of the adjustment ofthe stem 55 being predetermined from its previous position and anyappropriate shop measuring tool being used in connection with theadjustment in order 'to insure the accuracy of the positioning of thestem as adjusted.

For convenience of use the gage 52 is preferably permanently mounted atone end of the table 1 (Figures 1 and5). Thus the casing '53 projects"through an opening in a bracket59 and is suitably attached to thebracket, 'e. g., as by welding, the bracket serving for the-attachmentof the gage to an end of the table.

The use of the gage is illustrated in Figure 6. In such use the collet50 is inserted over one end of the shank'to an extent (sufficientlyindicated by dot and dash lines in Figure 6) merely sufiicient for thecollet to be stable upon the shank. The portion of the shank whichprojects .beyond the collet is thereupon inserted into the well 53, thelower end of the shank coming to rest upon the upper end of the stem 55.The collet Be is thereupon pushed downward upon the shank until itsmovement is arrested by the engagement of its split lower end upon theshoulder provided'by the upper end of the casing 53, this position ofthe collet being shown in full lines in Figure 6. At such time theportion of the shank which projects beyond the collet will have anextent equal "to the depth 01 the well 58, this extent being thedistance D. When the collet engages the upper 'end of the casing 53, itsjaws 5! will exercise a frictional grip upon the shank of such degreethat the shank and the collet are securely associated, that is to "saythe shank is held without any liability of accidental displacementrelatively to the collet whereby when'the shank is fitted in the machinethe distance D is maintainedexactly as determined by the cooperation ofthe collet and the gage 52. Using the collet'as-a'handle the shank isthereupon transferred from the gage 52 to the machine.

The mechanism for holding the shank in the machine The mechanism forholding the shank in the machine (Figures 1, 9, l1 and 12) is designatedgenerally as 69 and is located centrally of the length of the bar 9 towhich it is attached. This mechanism includes a cylindrical verticalcasin 6! open at its upper and lower ends, the casing 6| being mountedin a central opening in the bar 9 and projecting above and below thebar. The opening in the bar 9 in which the casing is fitted is ofenlarged diameter at its upper end in order to provide a shoulder forsupporting engagement by a circumscribing flange 62 formed upon thecasing, the upper face of the flange being flush with the upper face ofthe bar 9. The portion of the casing 6! which projects below the bar 9is formed with an internal terminal taper 63. The casing 6| encloses aclamping collet 5 3 which is generally similar in construction to thelocational collet 50. Thus the collet 64 is preferably in the form of anopen-ended sleeve which is split from its lower end to a point suitablyintermediate its length, thereby to provide a pair of clamping jaws 65of a semi-circular cross section. Each jaw 65 is formed with an externaltaper 66 which extends to its lower end, the opposing tapers 66presenting an inverted conical surface which bears against the taper 63of the casing 6i. The collet 54 projects beyond the casing BI and itsprojecting portion carries a circumscribing flange 61 which ispreferably in the form of a ring secured in fixed relation.

The collet 64 is formed with a central vertical opening, the diameter ofwhich conforms to the diameter of the shank. The shank is insertedthrough this opening and projects to a suitable extent beyond the lowerend of the collet. Whereas the jaws of the locational collet 50 maintaintheir secure engagement with the shank by reason of their inherentresiliency the jaws of the clamping collet as are positively urged intothe clamping engagement with the shank and are positively held in suchengagement. For this purpose downward pressure is positively applied tothe flange Bl. efiects the movement of the collet 64 (the shank movinwith it) from what may be called an idle position to a lower positionwhich may be called an active position. The movement of the collet thuseffected is so slight as to be scarcely sensually perceptible but it issufficient to cause the lower portions of the jaws 65 to exert verystrong frictional clamping pressure upon the shank, this pressure beingthe result of the cooperation of the tapers 63 and 66.

The application of downward pressure to the flange 57 is effected by amanually operated lever 88 pivotally connected to a bracket 69. Thisbracket consists of a straight horizontal plate 70 and a pair ofvertical ears H which extend upwardly from the plate at opposite sidesthereof. The plate it has an opening through which projects the portionof the casing 5| above the flange 62. The plate 70 rests upon the upperface of the bar 9 and has overhanging engagement with the flange 52,being thus utilized to secure the casing 5! to the bar 9 in the relationabove described. The bracket 69 is secured to the bar 9 by fastenings 72which project through the plate 70.

Thelever 68 is of general L-shaped outline and This downward pressure 12includesan arm '53 which provides a handle and preferably extends at asuitable upward inclination from the bracket 69. At its lower end thelever 68 has a forked formation which provides a pair of arms 74extending in upward relation to the lower end of the arm 13.

The arms M are arranged between the ears Ii, each arm being adjacent theinner face of a corresponding ear. Pins 75 at the upper ends of the arms14 pivotally connect the arms to the ears H. At their lower ends thearms '14 are provided adjacent their inner faces with vertical rollers16 which, when the arm E3 is depressed, bear upon the flange 61 andapply downward pressure to the clamping collet 64. The rollers 75 are solocated that when the arm 13 is fully depressed their axes will be veryslightly beyond (to the right, Figures 9 and 11 being considered) aperpendicular plane passing through the pivots 15, that is to sayslightly beyond dead center. This location of the rollers l6 insuresthat when the arm 13 is fully depressed the parts will be in lockedrelation, the clamping collet B l being thereby positively maintained inits active position. In order that the rollers may not be moved beyondtheir locking positions the bar 9 carries a post Ti which is locatedunder the arm 73 near its lower end and which provides a stop forpositively limiting the downward movement of the arm. When the arm itengages the post 17 the rollers 15 are in the locking relation abovedescribed. When the bit has been formed upon the shank S and the shankis to be withdrawn from the machine the pressure on the clamping colletis relieved by raising the arm 13 to a suitable extent.

In the insertion of the shank S into the clamping collet the locationalcollet 50 is used as a handle and the downward free movement of theshank through the clamping collet is continued until the lower end ofthe collet 5t engages the shoulder presented by the upper end of thecollet 64. The distance D above described then becomes the extent of theshank between its lower end and the upper end of the collet 64. When theshank has been inserted to the permissible extent through the clampingcollet the arm 13 is lowered until it engages the post 'il'. Suchdownward movement of the arm 73 effects the very slight movement of theclamping collet from its idle position to its active position, the shankS and the locational collet 50 participating in this movement. Duringthe formation of the bit the shank S is rigidly and securely held by thecollet 34. When the bit has been completed the cutters d8 are returnedto their normal lower positions. Thereupon the bar 9 is returned to itsupper position and the shank is removed from the machine. For thispurpose the arm 13 is raised in order to relieve the pressure on thecollet 64. The frictional bearing of the portions of the arms 74 whichsurround the pivots 15 upon the adjacent faces of the ears H is ofsufficient degree to maintain the lever 68 in the position to which itis moved when the arm 13 is raised. When the pressure on the clampingcollet has been thus relieved the shank is withdrawn by pulling itupward, the locational collet 58 being used as a handle. When the shankis pulled upward the clamping collet will move with it to the veryslight extent which is sufiicient for its jaws 65, by virtue of theirinherent resiliency, to spring outward from the shank and thus releaseit at which time the shank may be freely withdrawn from the collet 1364. When the jaws 65 release the shank the collet 84 will be in its idleposition in which it is conditioned for the insertion of another shankand a repetition of the operations.

The mil-Zing cutter units The milling cutter units I (Figures 1, l and11) are similar in construction and correspond in number to the numberof flutes to be cut. The machine shown in the drawings is for theformation of bits of cruciform cross section and hence includes fourunits I.

Each unit includes a milling cutter 48 which is mounted at the inner endof a horizontal shaft IS. The shafts l 8 are arranged in right angularrelation to one another as best shown in Figure 10. Two of the shafts inoffset relation extend longitudinally of the table I and the other two,also in offset relation, extend transversely of the table I. The millingcutters of the shafts which extend in the same directions confront oneanother in spaced relation and the four milling cutters, each spacedninety degrees from adjacent cutters, de-limit the passage 49 abovedescribed. Each unit 1 includes a mounting plate 19 for the directsupport of its shaft it. The plate I9 is provided at its upper end witha pair of inwardly projecting parallel ears 90. The shafts 18 arejournalled at their ends in suitable bearings (not shown) carried by theears 30. Each unit I includes gearing for the operation of its shaft 18,the gearing of the several units, of course, being drivensimultaneously. The gearing includes a vertical bevel gear 8I mounted infixed relation upon the shaft is and a bevel gear 82 meshing with thegear 8!. The gear 82 is mounted in fixed relation at the upper end of ashaft 83. The gear 82 is supported in operative relation to the gear BIby a bracket 82 which is attached by fastenings 85 to the plate It. Thebracket 84 provides a bearing for the shaft 83, the downwarddisplacement of which relatively to the bracket is prevented by aspacing collar 89 fitted on the reduced projectin upper portion of theshaft 83 and arranged between the hub of the gear 82 and the upper faceof the bracket 84. The mounting plate 19 has upward and downwardmovement in the operation of the machine and extends upward and outwardat a suitable angle to the vertical, its angular setting beingadjustably variable as will be later described. The shaft 83 istherefore driven by a universal shaft (Figure 11) designated generallyas $7, the two shafts being in slidable relation. The universal shaft Elincludes an upper section 88 and a lower section 89, these sections beinconnected by a universal joint 96 of any suitable form. The part of theshaft 83 within bracket 8 is formed with an axial recess 9! whichextends to its lower end. The shaft section 81 projects into the recess9i. The driving connection between the shaft section 81 and the shaft 83may include keys $2 on the shaft section which are slidable in keyways93 in the wall of the recess t I. Each cutter unit l includes asupporting frame designated generally as 94 (Figures 10 and 11), oneelement of this frame being a base plate 95 (Figures 3 and 11) whichrests upon the table I and which, for the purpose of positionaladjustment, is mounted for movement in directions at right angles to thehorizontal axis of the shaft E8 of the unit. The lower section 89 of theuniversal shaft extends vertically and is journalled in a supportingblock 96 secured by fastenings 97 to the inner end face of the baseplate 14 95. A spacing collar 98 is preferably interposed between theblock 96 and the adjacent part of the universal joint 90.

The table I is formed with a central opening 9d of circular outline toaccommodate the lower shaft sections 89, these projecting to a suitableextent below the table. The opening 99 also accommodates the blocks 96,the lower faces of which are preferably flush with the lower face of thetable. The opening 99, as best shown in Figure 3, is provided withangular extensions I00 to accommodate attachment flanges of the blocks96.

The gearing of the several units is driven from an electric motor IIlIwhich may be conveniently mounted upon one of the legs 2 (Figures 1 and2). The operative connections between the motor I (II and the universalshafts 9-! may conveniently be of chain and sprocket form (Figures 2, 3and 11). Each shaft section 89 carries at its lower end a sprocket I02and the upper end of the motor shaft *carries a sprocket I93, thesprockets I 02 and I93 being coplanar. A sprocket chain I I14 is engagedwith the sprockets I02 and I03 and serves to drive all of the universalshafts 81 in the same direction, the chain I04 being kept under suitabletension by a pivotally mounted spring biased tensioning arm I05 (Figure2) having a terminal roller for engagement with the chain.

Each cutter unit 1 in connection with the mounting of its shaft 78includes three serially connected plates (Figures 1, l0 and 11), namelyan inner plate, an intermediate plate and an outer plate. The innerplate is constituted by the mounting plate 139 above referred to. Theintermediate plate H36 may be called a guide plate in that it hasguiding cooperation with the mounting plate ill. The outer plate It! maybe called a supporting plate in that it is the part to which the guideplate it is attached. The mounting plate 19 is formed in its outer facewith a dovetail groove I98 which extends between its upper and lowerends. The guide plate I66 is formed on its inner face with a dove-tailprojection Hi9 which extends between its upper and lower ends and,conforming in cross sectional outline to the groove I98, fits within it.The projection 299 is, however, of somewhat less width than the groovein order to provide a clearance for a gib i It which is used inaccordance with standard shop practice and is secured in any suitablemanner to a wall of the groove I08. The projection m9 and the groove I98provide connections between the mounting plate l9 and the guide plateI96 which permit the upward and downward movement of the mounting plateupon the inner face of the guide plate, guiding the mounting plate insuch movement, and in all other respects positively couple these platesin rigid relation. The guide plate I93 is formed on its outer face witha dovetail groove III which extends transversely between its side faces.The supporting plate It? is formed on its inner face with a transverselyextending dove-tail projection H2 which conforms in cross sectionaloutline to the groove HI and fits within it. The projection I I2 isdimensioned to provide a clearance for a gib i I3 which is fittedbetween the upper face of the projection and the overlying face of thegroove I I I, the gib I 53 being suitably secured to the adjacent wallof the groove III. The projection H2 and the groove III positivelycouple the plates IE6 and till in rigid relation but permit a lateraladjustment of the position of the plate I96 relatively to the plate I01.This lateral adjustment is enabled by the universal joint of the shaft87 and is for the purpose of insuring accuracy in the centering of thecutters l8 relatively to one another, that is to say of insuringaccuracy in the symmetrical definition of the passage 49. Since thecorresponding plates of the several cutter units I (mounting plates I9,guide plates I96 and supporting plates I97) are of the same dimensionseach guide plate, as adjusted, will occupy the same position relativelyto its companion supporting plate as the guide plates of the otherunits. The adjustment, once made, is permanent for any set of cuttersand needs to be repeated only as there may be a substitution of some oneor more of the cutters or if, for any reason, it should become necessaryto disassemble or reassemble any one or more of the units I. Theadjustment in any case is minute in lineal extent and may be effected byhorizontal screws i 3 which bear against the side faces of thesupporting plate i9? and have threaded engagement in openings inbrackets I I5 carried by and projecting outward from the guide plate I95and suitably attached to its side faces.

The angularity of the paths in which the cutters 48 have their upwardand downward movement is varied in accordance with the particularpredetermined angularity of the bases of the flutes. For this purposethe plates "I9, I95 and III'I, serially connected as a group G, aremounted for angular, i. e. pivotal, adjustment. The cutter unitsupporting frame 5 includes a pair of parallel vertical side walls II 9suitably spaced and extending in upright relation from the base plate95. The supporting plate I9? is mounted near its lower end upon atransverse pivot pin II'I (Figures 1 and 11) which extends between theside walls H9. The plate III? is located between the side walls lid andits side faces are closely adjacent the inner faces of the walls IIE.When the angle of the Daths'of movement of the cutters is to beadjustably varied the plate group G is moved as a unit in the properdirection and through the proper degree about the pivot III, anysuitable shop measuring tool being used for the determination of thedegree of movement. The walls IIE are connected near their upper ends bya draw pin IIS, one end of which is tapped as at I I9 (Figure into oneof the walls and the other end of which carries a knurled head I25serving as a finger piece and bearing against the outer face of theother wall. The parts of the walls through which the draw pin H8 extendshave a certain measure of resiliency and normally are strongly heldagainst the side faces of the plate I57 by the draw pin H8, theconnected plates G thus being clamped in the particular positiondetermined upon. When the position of the group G is to be varied thedraw pin II 8 is backed off to permit the walls IIG to release the plateIfil, thereby to permit the free manual adjustment of the position ofthe plates G. When this adjustment has been made the pin I I8 istightened, thereby to secure the plates Gin the newly adjusted position.

The passage 49 may be varied in dimensions in order to accord withparticular predetermined cross-sectional dimensions of the bit. Ineffecting such variation the cutters, with their axes in the commonnormal plane H, are adjustably moved toward or away from one another,the degree and relative direction of adjustable movement being the samein each instance. For the purpose of such adjustable relativepositioning of the cutters the base plates 95 of the frames Mare mountedfor slidable adjustment upon the table in directions normal to the axesof the cutter shafts I8. Each base plate is accordingly confined in aguide channel provided by a pair of parallel guide bars I2I and I22, onelocated at each side of the base plate. The guide bars are secured tothe table I by bolt fastenings I23. The guide channels may beconveniently of dove-tail cross section. For cooperation with the guidesI2I and I22 each base plate is formed with longitudinally extendingrabbeted grooves I24 and I25, the walls of which extend from the sideand bottom faces of the base plate and the cross section of whichconforms to the cross-sectional outline of the guide channels, the guidebars conformably fitting within the grooves I24 and I25. In order toinsure the perfect alinement of the base plates 95 the table I is formedin its upper face with straight grooves I26 (Figures 10, 11 and 11a). Agroove I25 is provided for each base plate 95 and extends in thedirection of adjustable movement of the base plate, that is to say inthe same longitudinal direction as the base plate. One of the guidebars, e. g. the guide bar I 2|, is provided along its outer edge with alongitudinal rib I2! which projects downward from its bottom face andfits in the corresponding groove I26. In assembling the frames 94 of theunits I upon the table I the guide bars I2I are initially secured to thetable by their fastenings I23 with their ribs I21 located in the groovesI26. The frames as are then positioned upon the table, the rabbetedgroove I24 of each frame being engaged with the guide bar I2I. Thus theguide bars I2I are utilized to effect the perfect alinement of theframes 94. The guide bar I22 is then engaged with the other rabbetedgroove I25 and is moved to a position in which its fastenings I23 may beapplied. Each frame 94 is positively adjusted upon the table I by anadjusting screw I28 (Figures 10 and 11) which extends in the samelongitudinal direction as its companion base plate 95 and is rotatablymounted in a bracket I29 located behind the frame 94 and attached to thetable I by fastenings I30. Each frame 94 is formed above its plate 95with a web I3I having a threaded opening which is engaged by thethreaded portion of the screw I28. Accordingly as the screw I28 isturned in one direction or the other it will project to a greater orless extent rearward from the web I3I and the degree to which itprojects from the web, its head bearing against the rear face of thebracket I29, will determine the position of the plate 95 relatively tothe guide channel provided by the bars I2I and I22. In order to hold theframe 9 5 in any position to which it may be adjusted upon the table I alocking screw I32 is provided. The bracket I29 is formed with a threadedopening in which the threaded portion of the screw I32 engages. Thescrew I32 projects inwardly from the bracket I29 and is positionedrelatively to the bracket to cause its head to bear with suitablepressure against the rear face of the web I3I. Thereby the screw I32effectively locks the frame 92 in the position to which it is adjustedby the screw I28.

The mechanism for reciprocating the cutters The mechanism 8 (Figures 2,3, 4, 9 and 11) for effecting and controlling the upward and downwardmovement of the cutters 48 includes a series of cams I33, one for eachcutter. The cams I33 are of the movable wedge type and are the innerfaces of the blocks.

' plate.

- moved in opposite directions, 1. e. reciprocated,

to raise and lower the cutters. The cams are mounted upon the upper faceof a horizontal operating ring I34 to which they are rigidly secured byfastenings I35, the central opening I 36 of the ring registering withthe opening 93 in the table I. The shaft sections 89 project through theopening I3 and the sprockets I02 are located suitably below the ringI34. The movement of the cams I33 is produced by the rocking movement ofthe; ring I34. in its plane and about its radial center. The ring isguided in its rocking movement by a series of conformably curved blocksI3! secured to the table I and arranged adjacent the under face of thetable, the peripheral edge of the ring adjoining The ring is supportedupon ledges provided by plates I33 arranged below and secured to theblocks I31. The plates I33 are curved in conformity to the outline ofthe blocks and project inward from them, their projecting portionsproviding the ledges upon which the ring I34 rests. The blocks aresecured to the table I by fastenings I39 which are also utilized tosecure the plates I38 to the blocks. The guide plate I36 is formed onits inner face with a recess I40 of suitable depth and which extends toits lower end. The upper wall of the recess I 43 provides a shoulderI41. The recess I43 accommodates the upper portion of a post I42; theupper end of which is suitably spaced from the shoulder MI. The portionof the post I42 within the recess I43 is rigidly secured, as by screwfastenings, tothe base of the dove-tail groove M3 in the mounting plateI9. An expansive helical spring I43 is arranged in the recess I46between the post I 42 and the shoulder I41 and reacts against theseparts. The'post I42 projects downward from the group of connected platesG and is provided at its lower end with an antifriction roller I44 whichrides upon the surface of a corresponding cam I33. Clearances for thedownwardly projecting portion of the post I42 are provided byregistering recesses I45 and I46 in the plate 95 and the table Irespectively; the recesses I46-being formed as angular extensions of theopening 99' of the table i and being severally adjacent and at an angleto the recesses IEO. The opposite movements of the cams I33 may becalled advancing and retractile movements; In their advancing movements,which are clockwise (Figure 3 of the drawing being considered), the camsraise the posts I42 in opposition to the pressure of their loadingsprings I43 and thereby to a corresponding extent raise the mountingplates "I9. The cutters 48, the shafts I6, the bevel gears BI and 82 andthe shafts 83 participate in the upward and downward movements of themounting The springs I43 serve two purposes. One purpose is suitably toretard and cushion the upward movements of the mounting plates I9 inorder that these movements may not be too abrupt, thereby avoidingliability of injury to the cutters 43 and the shank S. The other purposeis to effect suitably more rapid downward movements of the plates I9than would result from dependence on gravity alone, the springs therebymaintaining the contact of the rollers 44 with the surfaces of the cams.When the cams have reached the limit of their advancing movement thecutting of the flutes has been completed and thereupon the camsare-retracted to permit the downward movements of the mounting plates 79and the return of the cutters 48 to their normal lower positions. thecutters in such return acting with planishing effect upon the flutes asabove described. During the upward and downward movements of themounting plates I9 the shafts 83 are continuously rotated by theuniversal shafts 81 but are slidable with relation to the universalshaft sections 88.

The extent of the upward movements or throw of the cutters 48 dependsupon the degree of inclination of the cam surfaces'and the extent of theadvancing, movements of the cams. These factors are selected to providefor a cutter throw of maximum degree, that is to say: a throw which willenable the cutters to cut flutes of the greatest length within themanufacturing range. It will be understood that cutters of differentdiameters may be used, ideal practice involving the selection of adiameter which will accord with the extent of the flutes to be formed.The ring I34 is rocked by parts which are operated and controlled by apneumatic system as hereafter described in detail. The lengthwiseadjustment of the frames 94 as eifeotedby the adjusting screws I28 ismany case of such slight extent and at such a comparatively slow ratethat the rollers I44 of the posts I42 will readily move in eitherdirection transversely of the cam surfaces as an incident of. theadjustment, the width of the cam surfaces being suchthat the rollers I44will engage them many position to which the frames 94may be adjusted.

The bar 9, as above explained, is mounted for pivotal movement in ahorizontal plane about the post I0 as an axis. In. the event that accessshould be required to some one or more of the units 1 for such purposesas cleaning, repair or substitution of parts the bar 9 may be swungabout the post I 0' as a pivot from the angular position which itnormally. occupies to an angular position at one side of the machine asshown in broken lines in Figure 9; Thereupon free access for anyrequired purpose may be had to any one or more of the units 1. When therequired work has been done and the units are again assembled in properrelation the bar 9 is then swung back into the angular position which itnormally occupies (Figures 13, 1'4 and 15) wherein what may be calledits free end abuts the base of therecess 26 of the standard 23.

The pneumatic actuating system The mechanism 29 and the cam ring I34 areoperated and controlled by apneumatic system which, generally speaking,includes two automatic valves of the type known in the trade asfour-way, a number of bleeder valves and various pipesconstituting theair flow lines. One of the four-way valves, I 4! is provided for theoperation and control of the mechanism 23 and the other four-way valveI43 is provided for the operation and control of the cam ring I34.

The purpose of convenience is served by locating the valves I41 and I48according to the showing of Figure 5 wherein the valve I4! is mountedupon the end faceof the table I at the right and rear sideof the tableand the valve I48is mounted upon the upper face of the table I adjacentits front side and its end face at the left.

The valves I4] and I48 are similar in construction and are-of a wellknown type (the"Ke11er type) which has been on the market for many yearsand can be purchased from industrial supply houses. However, anunderstanding of the system of pneumatic operation and control thepistons the bottom wall of the valve chest I52.

involves th e desc ription of various details of these valves.

These details are sufficiently shown in Figures 8 and 8a, it beingunderstood that the description is applicable to both of the valves. Thevalve construction is shown in these figures in relation to the variousair flow lines which are connected to it. Two reference numerals areapplied to each flow line, one indicative of the 7 cal dimensions and arod I 56 connecting the pistons. Since the pistons I54 and I are of thesame diametrical dimensions the valve unit is perfectly balanced andwill move in either axial direction accordingly as the pressure may berelieved upon one or the other of the outer faces of I54 and I55. Thecasing I50 is formed internally with aligning cylindrical guides I51 forthe respective pistons I54 and I55. The

outer ends of the casing I58 are provided with end heads I53. The pistonI54, its guide I51 and the adjacent casing head I58 provide a pressurechamber I59, the outer face of the piston I54 being a Wall of thischamber. The piston I55, its guide I51 and the adjacent head I58similarly provide a pressure chamber I at the opposite end of the valvechest, the outer face of the piston I55 being a wall of th chamber I60.The pistons I 54 and I55 are mounted upon the end portions of the rodI56. An axial duct or passage I6I of narrow diameter is formed in therod I56 and extends from end to end thereof, the ends of the duct I 6!communicating with the pressure chambers I59 and I60. The movement ofthe piston unit is in either direction of the longitudinal axis of therod I53 and such movement results in one of the pressure chambers beingprogressively reduced in volume and the other pressure chamber beingprogressively increased in volume. In connection with the movement ofthe piston unit air will flow from the pressure chamber which is beingreduced in volume through the duct I6! to the pressure chamber which isbeing increased in volume. The end heads I58 are provided with axiallylocated threaded openings I62. As furnished by the manufacturer theseopenings are closed by removable plugs (not shown).

The piston unit I53 operates a plate valve I64 which has slidingmovement upon the inner face 565 of the base late I49, the face I65providing The plate valve I66 is formed in itsunderface with a recessI66 for controlling the communication between certain ports to be laterdescribed. The plate of the valve chest I52.

The base plate I49 is formed with four laterallvextending ports I10,I1I, I12 and I13. The

ports I10 and I12 are open to one of the side faces of the :base plateand the ports HI and I13 are open to the opposite side face of the baseplate. The ports of each pair open to one side of the base plate areofiset with relation to the ports of the other pair open to the oppositeside of the base plate. The ports I10, "I, I12 and I13 extend slightlymore than half way through the base plate and at their inner ends are incommunication with angularly extending port I14, I15, I16 and I11,respectively, which are in open communication with the valve chest I52through the inner face I65 of the base plate. The port I12 is an exhaustwhich functions in both operative positions of the plate valve I64 andvents the compressed air to the atmosphere.

The piston unit I53 has two operative positions in one of which (whichmay be called its left position) the piston I54 is located at the leftend of the pressure chamber I59 (Figure 8 of the drawing beingconsidered) and in the other of which (Which may be called its rightposition) the piston I55 is located at the right end of the pressurechamber I60. The angular ports I14, I15, I16 and I11, considered as aseries, are arranged in succession along a longitudinal central line ofthe face I65. The plate valve I64 at no time covers the port I14. Whenthe piston unit I53 is in its right position the plate valve I64 coversthe angular ports I16 and I11 and establishes two paths of flow, one ofwhich is from the port I13 to the port I12 and through the recess I66and the other of which is from the port I10 to the port HI and throughthe valve chest I52. When the piston unit I53 is in its left positionthe plate valve covers the angular ports I16 and I15 and establishes twodifierent paths of flow, one of which is from the port I1I to the portI12 and through the recess I66 and the other of which is from the port;I10 to the port I13 and through the valve chest I52.

The features above described as I49 to I11 inclusive are common to thevalves I41 and I 48. The changes in the flow lines of air are effectedin the same way by both valves. The normal positions or relations of theparts of the valves are the same in both instances.

The compressed air for the system of pneumatic operation and control isdelivered by a line I18 from a storage tank. The line I18 communicateswith two branches I19 and I80, the branch I19 delivering to th valve I41and the branch I to the valve I48.

The normal position of the piston unit I53 is its right position asshown in Figure 8. In this position of the piston units (of the twovalves I41 and I 48) all parts of the machine are in their normalpositions andthe machine is, therefore, ready for the cycle ofoperationswhich are performed in the production of the drill bit. The operation ofthe machine is initiated by the manual actuation of a bleeder valve I8I(Figure 5) which is conveniently located adjacent the front of the tableI and is provided at the end of a bleed line I82 connected to the valveI41, the connection being with the head I58 at the left side of thevalve (Figure 8 being considered) and the bleed line being incommunication with the valve chest I52 through the opening I62. When thebleeder valve I 8I is actuated air is vented from the left end of thevalve chest with the result that the pressure upon the outer face of thepiston I54 is relieved and the piston unit is shifted to its leftposition.

The bleeder valve IBI is one of a series of bleeder valves incorporatedin the system of pneumatic operation, the remaining bleeder valve beingdesignated as I 83, I84 and I85 and being automatically operated insuccession. The bleeder valves I8I, I83, I84 and I85 are of a well knowntype and are similar in construction, their details being shown inFigure 8b. Each bleeder valve includes a casing I88 which provides achamber I81 in communication with a conical valve seat I88 externallyformed upon the inner end wall of the casing. The seat I88 accommodatesa normally closed valve I89 provided at the lower end of a stem I98which projects through the casing and through an opening in its outerend wall, the projecting portion of the stem carrying an operatingbutton I9I having a hemi-spherically curved surface. The valve I89 isnormally held in its closed position by a spring I92 arranged within thechamber I81 and reacting against a shoulder I93 formed on the casing I86and a shoulder I94 provided on the valve stem I98 near its upper end.The casing I88 is formed with vent openings I95 leading from the chamberI81. When the button I9I is pushed inward against the pressure of thespring I92 the valve I89 is moved away from its seat and air is ventedto the atmosphere through the chamber I81 and the vent openings I95. Thebuttons I9 I of the several bleeder valves are movable elements for thecontrol of the actuation of the different mechanisms with which thebleeder valves are severally associated.

The power for the operation of the mechanism 29 is delivered by'a pistonI98 which is movable in a, cylinder I91, th flow of air for theoperation of the piston I98 being controlled by the valve I 41. Thenormal position of the piston I98 is at the right end of the cylinderI91 (Figure being considered). When the piston I98 is moved to the leftend of the cylinder I91 the mechanism 29 is operated to effect the downward movement of the bar 9. When the piston I 96 is returned to itsnormal, position at the right end of the cylinder I91 the mechanism 29is operated to provide for the upward movement of the bar 9 to itsnormal position. The leftward movement of the piston I98 is governed bythe bleeder valve I8I and its return movement to the right is governedby the bleeder valve I85 which is provided at the end of a bleed lineI98 connected to the head I58 of the valve I41 opposite the head towhich the bleed line I82 is connected.

The power for the operation of the cam ring I34 is delivered by a pistonI99 which is movable in a cylinder 288, the flow of air for theoperation of the piston I99 being controlled by the valve I 48.Thenormal position of the piston I99 is at the right end of the cylinderI98 (Figure 5 being considered). When the piston I99 is moved to theleft end of the cylinder I98 the cam ring I 34 is operated upon itsadvancing stroke. When the piston I99 is returned to its normal positionat the right end of the cylinder 288 the cam ring is operated on itsretractile stroke. The leftward movement of the piston I99 is governedby the bleeder valve I83 and its return movement to the right isgoverned by the bleeder valve I84. The bleeder valve I83 is at the endof a bleed line 28I connected to an end head I58 of the valve I48. Thebleeder valve I84 is at the end of a bleed line 282 connected to thehead I58 of the valve I48 opposit the head to which thezline MI isconnected.

The air for moving the piston I98 to its normal position to the rightand for holding it in such position is delivered by a line 283 and theair for moving the piston I96 to the left and for holding it in suchposition is delivered by a line 288, the lines 283 and 284 beingpreferably flexible hose sections. One end of the line 283 is connectedto the left end of the cylinder I91 and the other end is connected tothe base plate I45 for direct communication with the port I1I. One endof the line 284' is connected to the right end of the cylinder I91 andits other end is connected to th base plate I45 for direct communicationwith the port I18. The air supply branch I19 for the valve I41 isconnected to th base plate I for direct communication with the port I10.The exhaust port I12v is preferably connected to an air exhaust pipe285'.

The air for moving the piston I99 to its normal position to the rightand for holding it in such position is delivered by a line 288 and theair for moving the piston I99 to the left and for holding it in suchposition is delivered by a line 281, the lines 289 and 281 beingpreferably flexible hose sections.

One end of the line 288 is connected to the left end of the cylinder 288and its other end is connected to the base plate I45 of the valve I48for direct communication with the port I1I. One end of the line 291 isconnected to the right end of the cylinder 288 and its other end isconnected to the base plate I 45 for direct communication with the portI13. The air supply branch M9 for the valve I41 is connected to the baseplate I85 for direct communication with the port I18. The exhaust portI12 of the valve M8 is preferably connected to an air exhaust pipe 288.

When the piston unit of the valve I41 is in its normal right positionair will flow from the delivery branch I19 through the ports 18 and I14into the valve chest I52 and thence through the ports I15 and I1! andthe line 293 to the left end of the cylinder I91 to effect the movementof the piston I 99 to the right. At the same time the air at the rightside of the piston I96 will escape through the line 284, ports I13 andI11, recess I88, ports I16 and I12 and exhaust pipe 285 to atmosphere.When the piston unit of the valve I48 is in its normal right position(Figure 8 being considered) the paths of flow will be identical, the airbeing delivered into the left end of the cylinder 288 through the line288 and at the same time the air at the right side of the piston I99escaping from the cylinder through the line 281.

When the piston unit of the valve I41 is in its left position (Figure 8being considered) air will flow from the delivery branch I19 through theports I18 and I14 into the valve chest I52 and thence through the portsI11 and I13 and the line-288 to the right end of the cylinder I91 toeffect the movement of the piston I99 to the left. At the same time theair at the left side of the piston will escape through the line 283,ports Ill and H5, recess I88, ports I18 and 812 and exhaust pipe 285 toatmosphere. When the piston unit of the valve I48 is in its leftposition the paths of flow will be identical, the

air being delivered into the right end of the cylinder 298 through theline 281 and at the same time the air at the left side of the piston I99escaping from the'cylinder through the line 288.

Support. for the cylinder I91 (Figures 9 and 13) is provided by the bar9 and the arm 32 of the mechanism 29. A split or two-part bracket brokenlines.

"2539 is mounted in fixed relation uponthe outer end of the cylinderI91. The inner part of the bracket 259 is provided with spacedhorizontal ears 2H) which provide a recess 2 that enables the bracket tobe fitted to the outer end portion of the bar 9. The bracket ispivotally connected to the bar 9 by a pin 2 I2 which extends through theears ZIQ. The rod 253 upon which the piston H6 is mounted is pivotallyconnected at its outer end as at 2M to the arm 92 of the mechanism 29.The pivotal connection 2I2 between the bracket 2G9 and the bar 9 enablesthe cylinder It? to swing in a horizontal plane in compensation for themovement of the pivot 2M through the arc of which the pivot 33 of thelever 3!} is the radial center.

The piston I96 in its movement to the left swings the lever 33' from theposition shown in full lines in Figure 9 to the position shown in Asabove explained this movement of the lever 38 results in the outwardmovement of the cam members and 39 and the downward movement of the bar9. The completion of the downward movement of the bar 9 is immediatelyfollowed by the actuation of the bleeder valve I89 for the purpose ofcausing the movement of the piston I99 to the left.

The bleeder valve I83 is mounted on an angle bracket 2!?) (Figures 9, 13and 1a) which is secured to the standard 23 at its inner side, the valveI83 being located adjacent the rear side of the bar 9 and projectingforwardly from the bracket 2I5. The cam member 33 of the mechanism 29 isutilized in connection with the actuation of the bleeder valve I83. Thedirect actuating element is an anti-friction roller 2I6 which moves withthe cam member 38 and, upon the completion of the downward movement ofthe bar 9, engages and depresses the button I91 of the valve I83 andthen releases it. The roller 2IS is carried by an arm 2II whichconveniently consists of a pair of plates. The arm 2I'I is ivotallyconnected as at 2I8 to a supporting block 2I9 carried by an anglebracket 229. The block ZIS is attached to the bracket 226 by a fasteningEM and the angle bracket is attached to the cam member 33 adjacent itsupper face by fastenings 222 which pass through the horizontal flange ofthe bracket. The arm 2I'I projects rearwardly from the block 2 I 9 andthe roller 2I6 is fitted between the free ends of the plates whichconstitute the arm, its pintle being mounted in these plates. The block2I9 is provided at its outer end with a projecting car 223 which extendsbetween the plates of the arm 2 I and in which the pivot ZIB is fitted.The block 2I9 is formed with shoulders 224 adjacent the ear 223 and thearm 2I7 is spring biased normally to rest against them. The arm ZI'I isheld rigid by the shoulders 224 during the outward movement of the cammember 38 and at the time when it engages and depresses the button ofthe valve I83 and moves beyond it, the continued outward movement of theroller 2I6 releasing the valve which thereupon resumes its normallyclosed condition. When the cam member 38 is moved inward upon the returnstroke of the arm 92 the arm 2I'I yields on its pivot when it engagesthe button of the valve I83 and rides over it. of course without anactuation of the valve. When the roller 2I6 during the inward movementof the cam member 38 passes beyond the valve I 83 the arm 2|! isrestored I to its normal position in which it is held against theshoulders 224.

The movement of the piston I99 to the left (Figures 3, 5 and 9 beingconsidered) which results from the actuation of the bleeder valve-I83effects the movement of the cam ring I34 through its advancing stroke.For this purpose the cam ring carries a rigidly attached arm 225(Figures 2, 3 and 9) which projects forwardly beyond the table I and isof such length that it may serve as a handle for the manual operation ofthe cam ring I34 if such should be required. The rod 22 8 upon which thepiston I99 is mounted is connected by a link 22! to the forwardlyprojecting part of the arm 225. The movement of the piston I99 to theleft eiiects a corresponding movement of the arm 22 5, that is to say amovement of the arm from its full line position shown in Figures 3 and 9to the position shown in broken lines in these figures during which thearm moves the cam ring I33 through its advancing stroke. The bleedervalve I84 is conveniently located adjacent the front of the table I.When-the arm 225 very nearly reaches the limit of its movement to theleft it engages and depresses the button I9I of the bleeder valve I84with the result that the piston unit I53 of the valve I48 is returned toits normal position, i. e. its right position, as shown in Figure 8.Thereby the flow of air in relation to the cylinder 260 i reversed withthe result that the piston I99 is returned to its normal position at theright end of the cylinder 200 and the arm 225 is restored to its normalposition as shown in full lines in Figures 3 and 9. The arm 225 duringits return movement efiects the movement of the cam ring I34 through itsretractile stroke, thereby returning the cam ring to its normalposition.

The bleeder valve I85 is conveniently mounted adjacent the front face ofthe table I. The arm 225 is utilized for its actuation and is operativeon its return stroke for this purpose. The actuation of the bleedervalve E85 is directly effected by a roller 228 which engages its buttonto move it inward, the operation being similar to that of the operationof the bleeder valve I83 by the roller 215. The roller 228 is carried byan arm 229 which is pivotally mounted upon a block 239, the arm 229 andblock 239 being similar in construction to the arm 2| I and block 2| 9above described. The block 239 is carried by the arm 225 and is mountedfor any positional adjustment that may be required. For the purpose ofpositional adjustment the block 239 is formed with a slot 23I and isconnected to the arm 229 by a fastener 232 which passes through theslot.

' When the roller 228 has actuated the bleeder valve I it passes beyondit, releasing the button with resultant closing of the valve. During thenext movement of the arm 225 to the left the engagement of the roller228 with the button of the valve I89 will result in the displacement ofthearm 229 whereby the roller rides over the button without actuatingit. The actuation of the bleeder valve 35 results in the shifting of thepiston unit 53 of the valve I4! to its normal right position with theconsequent movement of the piston I9 6 to its normal position at theright end of the cylinder I97.

Recapz'tulation of the cycle of operations The cycle of operations of.the machine may, for convenience, be briefly recapitulated as follows:The cutters 59 are driven at all times from the motor IUI. The shank Sis fitted in the clamping collet 64 and is secured by lowering the arm13. The operator then actuates the bleeder valve I8I by manuallydepressing its button I9I.

